U.S. patent application number 16/029490 was filed with the patent office on 2018-11-01 for catheter assembly.
This patent application is currently assigned to B. Braun Melsungen AG. The applicant listed for this patent is B. Braun Melsungen AG. Invention is credited to Kevin Woehr.
Application Number | 20180311490 16/029490 |
Document ID | / |
Family ID | 49302014 |
Filed Date | 2018-11-01 |
United States Patent
Application |
20180311490 |
Kind Code |
A1 |
Woehr; Kevin |
November 1, 2018 |
CATHETER ASSEMBLY
Abstract
A catheter assembly including a catheter hub being connectable
to a device for the infusion or withdrawal of fluids; a hollow
extension tube connected at its distal end to the catheter hub, the
extension tube connectable at its proximal end to a device for
infusing fluid into the chamber within the catheter hub; a valve
assembly disposed within the chamber of the catheter hub having a
first valve member and a second valve member preventing the flow of
fluid through the chamber to or from the proximal end of the
catheter hub. A needle guard assembly is also provided.
Inventors: |
Woehr; Kevin; (Felsberg,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
B. Braun Melsungen AG |
Melsungen |
|
DE |
|
|
Assignee: |
B. Braun Melsungen AG
Melsungen
DE
|
Family ID: |
49302014 |
Appl. No.: |
16/029490 |
Filed: |
July 6, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15042026 |
Feb 11, 2016 |
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16029490 |
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14890419 |
Nov 10, 2015 |
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PCT/EP2014/067573 |
Aug 18, 2014 |
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15042026 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61M 2039/064 20130101;
A61M 2039/242 20130101; A61M 39/24 20130101; A61M 2039/062
20130101; A61M 25/0618 20130101; A61M 25/0606 20130101; A61M
25/0693 20130101; A61M 25/0097 20130101; A61M 25/0625 20130101;
A61M 39/22 20130101; A61M 5/36 20130101; A61M 2039/066
20130101 |
International
Class: |
A61M 39/24 20060101
A61M039/24; A61M 25/00 20060101 A61M025/00; A61M 25/06 20060101
A61M025/06; A61M 39/22 20060101 A61M039/22; A61M 5/36 20060101
A61M005/36 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 21, 2013 |
GB |
1314953.9 |
Aug 29, 2013 |
GB |
1315401.8 |
Oct 31, 2013 |
CN |
201310527778.3 |
Oct 31, 2013 |
CN |
201320679130.3 |
Claims
1. A catheter assembly comprising: a needle attached to a needle
hub and projecting through a catheter hub and a catheter tube in a
ready to use position with a needle tip extending out a distal
opening of the catheter tube; said catheter hub comprising a body
defining an interior cavity and an open proximal end with a female
Luer; a valve comprising a disc section comprising at least one
slit and a tubular portion; a valve opener for opening the at least
one slit of the disc section positioned at least in part in the
female Luer of the catheter hub; a needle guard assembly comprising
a housing having a distal end and a proximal end and a lengthwise
axis between the distal and proximal ends, the distal end of the
housing being coupled to the proximal end of the catheter hub; a
needle guard disposed within the housing, the needle guard
comprising: a needle trap moveable between a ready position, in
which the needle trap is held to one side of the needle with the
needle extending through the housing, and a protected position, in
which the needle trap blocks a sharpened needle tip of the needle,
said needle trap comprising a first end and a second end; a
resilient arm biasing the needle trap into the protected position,
the resilient arm bearing against an inner wall of the housing to
urge the needle trap into the protected position; and a coupling
arm coupling the housing to a proximal end of the catheter hub in
the ready position; a lateral or side member extending proximally
from the needle trap configured to prevent the needle from moving
laterally out of the needle trap; and wherein the coupling arm is
attached to the second end of the needle trap along a line
extending generally perpendicularly to the lengthwise axis of the
housing.
2. The catheter assembly according to claim 1, wherein the needle
trap comprises a second lateral or side member extending in a
proximal direction from the needle trap.
3. The catheter assembly according to claim 1, wherein the needle
trap comprises a retaining member preventing movement of the needle
tip out of the needle trap.
4. The catheter assembly according to claim 1, wherein the needle
guard housing has a portion extending into a proximal end of a
catheter hub in the ready position.
5. The catheter assembly according to claim 1, wherein the needle
trap is pivotally attached at the first end of the needle trap to
the resilient arm.
6. The catheter assembly according to claim 5, wherein the coupling
arm is pivotally connected to the second end of the needle
trap.
7. The catheter assembly according to claim 1, wherein the coupling
arm comprises an opening therein for accommodating the needle
extending through the opening in the ready position, movement of
the needle trap from the ready position to the protected position
causing the coupling arm to release the housing from the catheter
hub.
8. The catheter assembly according to claim 1, wherein the needle
guard housing comprises a proximal wall having an opening therein
for receiving the needle extending through the opening in the
proximal wall, wherein a region of the proximal wall adjacent the
opening comprises a reinforcement of a material that differs from a
material that forms the housing and the reinforcement comprising an
opening, the opening of the reinforcement being configured to
engage a bulge on the needle having a radial dimension that is
greater than that of the opening of the reinforcement.
9. A catheter assembly comprising: a catheter hub comprising a
proximal end, a distal end, an exterior surface, and an interior
surface defining an interior cavity, and wherein the proximal end
comprises a female Luer; a catheter tube extending from the distal
end of the catheter hub comprising a lumen and an open distal end;
a needle comprising a needle tip, a bulge located proximally of the
needle tip, and a proximal end, and wherein the needle extends from
a needle hub and projects through the catheter hub and the catheter
tube with the needle tip located distally of the open distal end in
a ready to use position; a valve comprising at least one slit and a
valve opener having an actuation end for opening the at least one
slit; the valve and the valve opener located in the interior cavity
of the catheter hub; a needle guard assembly comprising a housing
having the needle passing therethrough, said housing comprising a
distal end and a proximal end defining a lengthwise axis
therebetween, the distal end of the housing coupled to the proximal
end of the catheter hub and a needle guard is disposed inside the
housing of the needle guard assembly, the needle guard comprising:
a needle trap moveable between a ready position, in which the
needle trap is held to one side of the needle, and a protected
position, in which the needle trap is translated from the one side
of the needle to a blocking position distal of the needle tip of
the needle to block the needle tip, said needle trap comprising a
first end and a second end; a resilient arm having a first end and
a second end, the needle trap and the resilient arm being foldable
together to one side of the needle in the ready position; a
coupling arm coupling the housing to the proximal end of the
catheter hub, the coupling arm comprising a first end and a second
end; and a lateral or side member extending proximally from the
needle trap, the lateral or side member configured to prevent the
needle from moving laterally out of the needle trap; and wherein
the first end of the coupling arm is attached to the needle trap at
the second end of the needle trap along a line extending generally
perpendicularly to the lengthwise axis of the housing.
10. The catheter assembly according to claim 9, wherein the first
end of the needle trap is pivotally attached to the first end of
the resilient arm.
11. The catheter assembly according to claim 9, wherein the second
end of the needle trap is pivotally attached to the first end of
the coupling arm.
12. The catheter assembly according to claim 9, wherein a portion
of the housing of the needle guard assembly extends into the
proximal end of the catheter hub in the ready position.
13. The catheter assembly according to claim 9, wherein the needle
trap has two sides and an apex therebetween.
14. The catheter assembly according to claim 9, wherein the needle
trap comprises a retaining member preventing movement of the needle
tip out of the needle trap.
15. The catheter assembly according to claim 9, wherein the housing
of the needle guard assembly comprises a proximal wall having an
opening therein, the needle extending through the opening in the
proximal wall, wherein a region of the proximal wall adjacent the
opening comprises a reinforcement of a material that differs from a
material that forms the housing and the reinforcement comprising an
opening, the opening of the reinforcement being configured to
engage a bulge on the needle having a radial dimension that is
greater than that of the opening of the reinforcement.
16. The catheter assembly according to claim 9, wherein the needle
trap, the resilient arm, and the coupling arm are integrally formed
as a single component.
17. The catheter assembly according to claim 9, wherein the valve
further comprises a tubular portion.
18. The catheter assembly according to claim 9, wherein the
catheter hub comprises a side port and a tubing attached to the
side port.
Description
FIELD OF ART
[0001] The present invention relates to a catheter assembly, in
particular to an intravenous catheter assembly.
BACKGROUND OF THE INVENTION
[0002] Intravenous (IV) catheters are used to access a vein of a
patient, in particular for the provision of fluids to the patient
or the removal of fluid, especially blood, therefrom. The IV
catheter can be primed with a sterile solution to remove air from
the device prior to puncturing the patient. This reduces the risks
of the patient developing an air embolism.
[0003] An IV catheter assembly comprises a catheter extending from
the distal end of a catheter hub. A needle extends through the
catheter hub and the catheter, such that the sharpened tip of the
needle extends beyond the distal end of the catheter. A typical
procedure for insertion of the catheter into the vein of the
patient requires the healthcare worker to insert the sharpened
needle tip and catheter into the patient to locate the vein. Once
the needle tip is located in the vein, the healthcare worker
manually forwards the catheter into the vein by sliding the
catheter along the shaft of the needle in the distal direction.
Once the catheter is properly located in the vein, the needle is
withdrawn. The catheter is then secured by taping the catheter hub
to the skin of the patient. The vein may then be accessed for the
infusion or removal of fluids through the catheter hub and the
catheter.
[0004] To control the flow of fluids through the catheter and the
catheter hub, in particular to prevent blood leaving the vein
through the catheter, it is known to provide a valve in the
catheter hub.
[0005] A device for the drainage or infusion of liquids from or to
a patient is disclosed in EP 2 268 480. In one embodiment, the
device comprises a catheter hub having a catheter extending
therefrom. The catheter hub is provided with a flexible valve
therein for controlling the flow of fluid through the catheter hub.
A valve opener is provided to open the valve, when fluid is to be
infused or withdrawn through the proximal end of the catheter hub.
EP 2 268 480 discloses providing the catheter hub with a port
extending laterally therefrom. A flexible cylindrical seal extends
circumferentially around the inside the catheter hub in line with
the port.
[0006] U.S. Pat. No. 5,098,405 concerns a side ported catheter
adapter with a one piece integral combination valve. The valve is
disposed within a hub of the adapter so as to close the bore of the
adapter and the side port. The valve assembly comprises a generally
cylindrical body extending circumferentially around the interior of
the hub in line with the port. The valve assembly further comprises
a conical valve element, permitting the flow of fluid into the
catheter from the proximal end of the hub. The device of U.S. Pat.
No. 5,098,405 does not permit fluids to be removed from the patient
and only allows fluids to be infused to the patient through either
the proximal end of the adapter hub or the port.
[0007] A medical connector is described and shown in WO 96/40359.
The connector comprises a body having a primary conduit
therethrough and a port. A generally cylindrical valve is located
within the body in line with the port. A tab extends from the valve
into the port. The valve is normally open, permitting the flow of
fluid along the primary conduit. Depression of the tab in the port
closes the valve across the primary conduit, preventing the flow of
fluid therealong and allowing fluid to be infused to or withdrawn
from the connector through the port.
[0008] Of more relevance, a catheter apparatus with infusion port
and valves is disclosed in WO 2008/052791. The apparatus comprises
a hollow catheter extension, the distal end of which can be
connected to a catheter. A connecting device is provided on the
proximal end of the extension. A port extend radially from the
extension and opens into the bore of the extension. A valve
assembly is disposed within the extension in line with the port and
comprises a first, generally cylindrical valve element closing the
port. A second valve element prevents the escape of blood from the
extension through the bore in the proximal direction. The second
valve element is formed as a two-way valve, so as to permit the
flow of fluids in either the distal or the proximal direction.
[0009] More recently, WO 2008/052790 discloses a catheter assembly
and components thereof. The assembly comprises a valve disposed in
the catheter hub and a valve opener. The valve opener is configured
to be pushed by an IV set luer connector to open the valve, to
allow fluids to be passed through the catheter. A tip protector,
operable to cover the tip of the needle as the needle is withdrawn
from the catheter through the catheter hub, may be provided within
the valve opener.
[0010] WO 2012/009028 discloses a flushable catheter assembly. The
assembly comprises a catheter adapter having a septum disposed
therein. A septum activator is provided to selectively open the
septum and allow fluid to flow through the catheter adapter when a
coupler is attached to the proximal end of the catheter
adapter.
[0011] A catheter assembly is disclosed in DE 202007006190 U1.
[0012] WO 2004/032995 discloses a method of delivering a local
anesthesia and a catheter and needle assembly for use in the
same.
[0013] A safety shield for a needle is disclosed in WO
2005/042073.
[0014] A safety catheter comprising a needle point lock is
described and shown in U.S. Pat. No. 5,697,907.
[0015] Needle protector devices and assemblies are described in GB
2,343,118.
[0016] More recently, WO 2013/016373 discloses a vascular access
assembly and a safety device to protect a clinician from accidental
needle stick injuries.
[0017] There is a need for an improved catheter assembly, in
particular one that provides for increased control of the infusion
and withdrawal of fluids to and from the patient through the
catheter.
SUMMARY OF THE INVENTION
[0018] According to the present invention, there is provided a
catheter assembly comprising:
[0019] a catheter hub having a chamber therein, the catheter hub
having a distal end and a proximal end, the catheter hub being
connectable at its proximal end to a device for the infusion or
withdrawal of fluids to or from the chamber within the catheter
hub;
[0020] a hollow tubular catheter having a proximal end and a distal
end, the catheter being connected at its proximal end to the distal
end of the catheter hub, the interior of the catheter opening into
the chamber within the catheter hub;
[0021] a needle having a sharpened needle tip, in a ready position
the needle extending through the chamber in the catheter hub and
the catheter with the needle tip extending beyond the distal end of
the catheter;
[0022] a hollow extension tube having a distal end and a proximal
end, the extension tube being connected at its distal end to the
catheter hub between the proximal and distal ends thereof, the
extension tube opening at its distal end into the chamber within
the catheter hub, the extension tube connectable at its proximal
end to a device for infusing fluid into the chamber within the
catheter hub;
[0023] a valve assembly disposed within the chamber of the catheter
hub, the valve assembly comprising: [0024] a first valve member
closing the distal end of the extension tube and openable under the
action of a pressurised fluid within the extension tube; and [0025]
a second valve member preventing the flow of fluid through the
chamber to or from the proximal end of the catheter hub, the second
valve member being a two-way valve and openable to permit the flow
of fluid through the chamber in the catheter hub in both a proximal
and a distal direction.
[0026] The device of the present invention comprises a catheter
hub. The catheter hub is hollow and has an internal chamber
therein, the internal chamber being open at both the proximal and
distal ends of the catheter hub. The catheter hub may be formed as
a single piece. Alternatively, the catheter hub may be formed as
two or more separate pieces connected together.
[0027] The catheter hub is formed at its proximal end to be
connectable to a device for infusing fluid into the patient or
removing fluid from the patient, such as a syringe. Such devices
are known in the art and will be familiar to the person skilled in
the art. In particular, the inner wall of the proximal end of the
catheter hub defining the chamber is provided with an internal Luer
taper, that is a female Luer taper, allowing standard fittings
having a standard male Luer taper to be connected to the proximal
end of the catheter hub. The person skilled in the art will be
familiar with the Luer taper standard and its requirements.
[0028] In one embodiment, the catheter hub comprises a distal hub
portion and a proximal hub portion. The proximal hub portion is as
hereinbefore described and is connectable to a device for infusing
fluid into or removing fluid from the patient. The distal hub
portion may have any suitable form. In one embodiment, the distal
hub portion has a generally flattened form, such that the catheter
hub lies flatter against the skin of the patient and protrudes less
from the patient's skin in use. More preferably the distal hub
portion comprises wing members extending from opposing sides of the
distal hub portion. The wing members increase the stability of the
catheter assembly, in particular when the catheter has been
inserted into the vein of the patient, and may be used to secure
the catheter hub to the skin of a patient, for example by way of
adhesive tape. In this way, movement of the catheter hub and the
catheter is restricted, in turn reducing the occurrence of
phlebitis of the vein of the patient.
[0029] A hollow tubular catheter is connected to the catheter hub
and extends from the distal end of the catheter hub.
[0030] The catheter assembly further comprises a needle having a
sharpened needle tip and a bore therethrough. In a ready position,
the needle is connected at its proximal end to a needle hub, as is
known in the art, and extends through the catheter hub and the
catheter in a ready position. In the ready position, the sharpened
needle tip is distal of the distal end of the catheter, allowing
the needle and the catheter to be introduced into a vein of the
patient, in known manner. The needle hub preferably has a chamber
therein in communication with the bore in the shaft of the needle,
whereby blood flashback in the needle hub chamber may be observed
by the user to indicate proper placement of the needle in the vein,
in a known manner. The needle hub chamber is typically plugged at
its proximal end with a vented plug that allows air to vent from
the chamber, but not blood to flow through the plug.
[0031] As the needle tip is withdrawn into the hollow tubular
catheter a secondary blood flashback occurs between the outside of
the needle and the inside of the catheter.
[0032] A condition for both the primary and secondary blood
flashback is that the air in the catheter device can be displaced
by the blood as the air is vented out of the proximal end of the
device.
[0033] In one embodiment, the needle is provided with an opening,
such as a slot, in the shaft of the needle in the distal end
portion of the needle and spaced from the sharpened needle tip. In
the ready position, the slot is disposed within the tubular
catheter. In use, once the needle tip has been inserted into the
vein, blood may flow along the bore in the needle, through the slot
and into the catheter around the needle shaft. The blood can then
flow from the catheter into the catheter hub, to provide a
flashback to the user.
[0034] The catheter assembly of the present invention further
comprises a hollow extension tube having a distal end and a
proximal end. The extension tube is flexible. The extension tube is
connected at its distal end to the catheter hub between the
proximal and distal ends thereof. Preferably, the distal end of the
extension tube is connected to the distal portion of the catheter
hub. The extension tube opens at its distal end into the chamber
within the catheter hub, to allow fluid to flow between the
extension tube and the internal chamber. The extension tube is
connectable at its proximal end to a device, such as a syringe, for
infusing fluid into the chamber within the catheter hub. For
example, the extension tube may be provided at its proximal end
with a connection hub, preferably a hub having a female Luer
taper.
[0035] In use, fluid may be introduced into the catheter hub and
the catheter by way of the extension tube. By having the device for
introducing fluid connected at the proximal end of the extension
tube, it may be located away from the catheter hub and the catheter
located in the vein of the patient. By having the extension tube
flexible, movement of the catheter hub and the catheter as a result
of the action of connecting or disconnecting the fluid delivery
device at the proximal end of the extension tube is reduced or
eliminated. This in turn reduces the occurrence of phlebitis of the
vein in the region of the catheter.
[0036] The catheter assembly comprises a valve assembly disposed
within the internal chamber of the catheter hub. The valve
assembly, when closed, prevents the flow of fluid between the
extension tube and the internal chamber of the catheter hub and the
flow of fluid in either the proximal or distal direction through
the internal chamber. The valve assembly comprises a first valve
member, which may be opened to permit fluid to flow from the
extension tube into the internal chamber of the catheter hub. In
this respect, the valve assembly may be a one-way valve between the
extension tube and the internal chamber of the catheter hub. The
valve assembly comprises a second valve member, which may also be
opened to permit fluid to be supplied from the proximal end of the
catheter hub in the distal direction to the catheter or to allow
fluid to be withdrawn in the proximal direction from the catheter
to the proximal end of the catheter hub. In this way, the valve
assembly is operable as a two-way valve to control fluid flow
through the catheter hub to and from its proximal end.
[0037] The first valve member controls the flow of fluid between
the extension tube and the internal chamber of the catheter hub. In
a preferred embodiment, the first valve member comprises a
flexible, resilient valve body. Under the action of increased fluid
pressure in the extension tube, the valve body yields, opening the
distal end of the extension tube and permitting fluid to enter the
catheter hub. The valve body is preferably a tubular body, in
particular disposed within the internal chamber of the catheter hub
in contact with the inner surface of the wall of the catheter hub.
The valve body and the portion of the internal chamber of the
catheter hub in which it is disposed may be cylindrical or, in one
embodiment, elliptical, in cross-section.
[0038] The first valve member may comprise one or more slits
therein, aligned with the distal opening of the extension tube and
for the passage of fluid therethrough. If the first valve member
has one or more slits therein, then it can act as a two way valve
and blood or other bodily fluids can be removed through the slits
and extension line into a suitable device, such as a syringe or a
vacuum collection tube.
[0039] The valve assembly comprises a second valve member. As noted
above, the second valve member controls the flow of fluid through
the internal chamber of the catheter hub to and from the proximal
end thereof. The second valve member is disposed in the internal
chamber of the catheter hub in a position proximal to the distal
opening of the extension tube and the first valve member. In one
embodiment, the second valve member comprises a flexible, resilient
valve disc extending laterally across the internal chamber of the
catheter hub. The disc is provided with one or more closable
openings, such as slits, therein, in particular one or more
radially extending slits.
[0040] The valve assembly may be retained within the internal
chamber of the catheter hub by any suitable means. In one
embodiment, the valve assembly is retained by friction between the
valve members and the inner surface of the catheter hub.
Alternatively, the valve assembly may engage with one or more
recesses or protrusions formed in the inner surface of the catheter
hub.
[0041] In the ready position, the needle shaft extends through the
valve assembly. The second valve member preferably seals around the
shaft of the needle in the ready position, more preferably in a
manner that allows gas to vent through the second valve member in
the proximal direction, but prevents blood from passing the second
valve member. In embodiments in which the second valve member
comprises a disc having one or more slits therein, this can be
achieved by appropriate arrangement of the or each slit, such that,
in the ready position, the or each slit is held open by the needle
shaft a sufficient amount to allow the passage of gas but prevent
the passage of blood therethrough.
[0042] The second valve member may open under the action of a
difference in fluid pressure across the valve member. In
particular, the second valve member may open under the action of an
increased fluid pressure on the proximal side of the valve, to
allow fluid to be infused into the catheter and vein of the
patient. Similarly, the second valve member may open under the
action of a reduced pressure on the proximal side of the valve, to
allow fluid to be withdrawn from the catheter and the vein.
[0043] In one embodiment, the catheter assembly further comprises a
valve opener disposed within the chamber in the catheter hub. The
valve opener is disposed within the internal chamber of the
catheter hub proximally of the valve assembly. The valve opener is
moveable between a closed position, in which the second valve
member is closed, and an open position in which the second valve
member is open. The valve opener is moved in the proximal direction
to the open position by the insertion of a device into the proximal
end of the catheter hub, such as a syringe or other male fitting.
The valve opener is urged into the closed position by the action of
the second valve member closing, for example by the resilience of
the valve disc. The valve opener preferably has a passage extending
longitudinally therethrough and/or around for the passage of
fluid.
[0044] Movement of the valve opener in the distal direction is
limited by the valve assembly. Preferably, means are provided to
limit the movement of the valve opener in the proximal direction.
In one embodiment, the inner surface of the catheter hub is
provided with one or more protrusions to engage with the valve
opener.
[0045] In the ready position, the needle shaft extends through the
valve opener. One preferred form of valve opener comprises a stem,
having a passage therethrough, and a head portion at the distal end
of the stem, having a passage therethrough. In use, a device
inserted into the proximal end of the catheter hub contacts the
stem of the valve opener, urging the valve opener from the closed
position into the open position. As the valve opener is moved
proximally into the open position, the head portion is urged into
contact with the second valve member, opening the valve
assembly.
[0046] The stem may comprise a tube, with the needle extending
through the tube in the ready position. Alternatively, the stem may
comprise one or more legs extending proximally from the head
portion. In one embodiment the region of the head portion
contacting the second valve member is generally domed or
frusto-conical.
[0047] In a preferred embodiment, the catheter device of the
present invention is a safety device and comprises a needle guard
assembly. The needle guard assembly acts to cover and block the
sharpened needle tip as the needle is withdrawn from the catheter
in the proximal direction and moved from the ready position into a
protected position. In this way, the risk of a needle stick injury
occurring is reduced or avoided.
[0048] The needle guard assembly may be disposed wholly or partly
within the internal chamber in the catheter hub. In particular, the
needle guard may be disposed within the catheter hub, such that the
needle is in its protected position with the sharpened needle tip
blocked by the needle guard assembly while the needle tip is within
the catheter hub. Examples of preferred needle guard assemblies for
use in such embodiments are disclosed in WO 99/08742. The needle
guards of WO 99/08742 are of a passive type, that is the needle tip
is blocked by the needle guard as the needle is withdrawn from the
ready position into the protected position, without the user having
to take any additional actions over and above those required with
the use of standard or non-safety devices. Passive needle guards of
this type are preferred.
[0049] Alternatively, the needle guard assembly may be disposed
outside the catheter hub, in particular proximal of the catheter
hub. In one preferred embodiment, the needle guard assembly
comprises a needle guard housing having a needle guard chamber
therein. A needle guard is preferably disposed in the chamber. The
needle guard housing may have a portion extending into the proximal
end of the catheter hub. For example, the needle guard housing may
have a distal end portion comprising a male taper, such as a
standard Luer taper, for engaging with a female taper in the
proximal end portion of the catheter hub. Alternatively, the needle
guard housing may reside completely outside the catheter hub.
[0050] The needle guard assembly is preferably releasably engaged
with the catheter hub. In one preferred embodiment, the needle
guard assembly is engaged with the catheter hub with the needle in
the ready position. Movement of the needle to the protected
position, in which the needle tip is blocked, releases the needle
guard assembly from the catheter hub.
[0051] Most preferably, in the protected position, the needle tip
is disposed within the needle guard housing and the needle tip is
blocked within the housing by the needle guard.
[0052] A needle guard is disposed within the needle guard housing.
The needle guards of WO 99/08742 may be employed within the needle
guard housing.
[0053] One particularly preferred form of needle guard for use in
the catheter assembly as hereinbefore described comprises at least
one arm, the arm being moveable from the ready position into a
blocking position in which the sharpened needle tip is blocked. The
at least one arm preferably has a distal end portion for extending
in front of and blocking the needle tip in the blocking position.
The at least one arm may extend parallel to the needle in the ready
position or, alternatively may cross the shaft of the needle in the
ready position.
[0054] In a preferred embodiment, the needle guard comprises a
first arm and a second arm. One or, preferably both, of the first
and second arms may comprise a distal end portion for blocking the
needle tip. The first and second arms may extend along opposing
sides of the needle shaft in the ready position. Alternatively, the
first and second arms may intersect and cross the needle shaft in
the ready position. As noted above, at least one of the first and
second arms is provided with a distal end portion for blocking the
needle tip in the protected position. In embodiments in which both
the first and second arms have a distal end portion, it is
preferred that the distal end portions are offset with respect to
one another. In this way, the distal end portions may engage over
the needle tip.
[0055] The first and second arms may be of the same length or of
different lengths. Preferably, the first and second arms are of
different lengths, especially when both arms are provided with a
distal end portion. If a single distal end portion is present, it
is preferably disposed on the longer of the first and second
arms.
[0056] At least one of the distal end portions is provided with an
endmost portion that is curved inwards at its free edge. In this
way, it is ensured that the needle tip is covered, even if an
attempt is made to push the needle guard in the proximal direction,
that is back from the protected position, along the needle shaft.
The inwardly curved endmost portion acts to hook onto the needle
tip, so as to prevent movement of the needle guard in the proximal
direction and to prevent the needle tip becoming exposed.
[0057] The needle guard comprising one or more arms may be in the
form of a resilient or spring clip needle guard.
[0058] In a preferred embodiment, the needle guard within the
housing comprises a needle trap moveable between a ready position,
in which the needle trap is held to one side of the shaft of the
needle extending through the housing, and a protected position, in
which the needle trap extends across the needle tip and blocks the
sharpened needle tip of the needle within the housing. The needle
guard further comprises a resilient arm biasing the needle trap
into the protected position. The resilient arm bears against the
inner wall of the housing to urge the needle trap into the
protected position. In addition, the needle guard comprises a
coupling arm moveable by the needle trap. In the ready position the
coupling arm couples the housing to the proximal end of the
catheter hub. Movement of the needle trap from the ready position
to the protected position moves the coupling arm to release the
housing from the catheter hub.
[0059] Accordingly, in a further aspect, the present invention
provides a needle guard assembly for a catheter assembly, the
needle guard assembly comprising:
[0060] a housing for receiving a needle extending therethrough and
having a distal end and a proximal end, the housing being
connectable at its distal end to the proximal end of a catheter
hub;
[0061] a needle guard disposed within the housing, the needle guard
comprising:
[0062] a needle trap moveable between a ready position, in which
the needle trap is held to one side of the shaft of the needle
extending through the housing; and a protected position, in which
the needle trap blocks the sharpened needle tip of the needle
within the housing;
[0063] a resilient arm biasing the needle trap into the protected
position, the resilient arm bearing against the inner wall of the
housing to urge the needle trap into the protected position;
[0064] a coupling arm, in the ready position the coupling arm
coupling the housing to the proximal end of the catheter hub,
movement of the needle trap from the ready position to the
protected position moving the coupling arm to release the housing
from the catheter hub.
[0065] The needle trap may be connected at one end to the resilient
arm. In a preferred embodiment, the needle trap is pivotally
attached at a first end thereof to the resilient arm. The
resilience of the resilient arm may be provided partly or wholly by
resilience in the pivotal connection between the needle trap and
the resilient arm. In one embodiment, the needle trap and the
resilient arm are folded together on one side of the needle shaft
when in the ready position, such that the needle trap overlies the
resilient arm.
[0066] In the protected position, the needle trap extends distally
across the sharpened needle tip, thereby blocking the needle tip
and preventing a needle stick injury. The needle trap may comprise
one or more lateral members extending in the proximal direction
from each side of the needle trap. The lateral members act to
retain the needle trap in position relative to the sharpened needle
tip, in particular preventing the needle tip from emerging to one
side of the needle trap. In use, the needle trap transitions
between the ready position, across the needle tip and into the
protected position. Further, the needle trap may comprise a
retaining member preventing the needle trap from moving in the
reverse direction, that is towards its ready position, relative to
the needle.
[0067] The needle guard further comprises a coupling arm. In the
ready position, the coupling arm engages with the catheter hub, to
hold the needle guard assembly on the proximal end of the catheter
hub. In a preferred embodiment, the coupling arm engages with the
outside of the catheter hub, for example with a flange on the
proximal end of the catheter hub. The coupling arm is moved by the
needle trap transitioning from the ready position to the protected
position out of engagement with the catheter hub, thereby releasing
the needle guard assembly from the catheter hub. In this way, the
needle guard assembly is only released from engagement with the
catheter hub once the sharpened needle tip is blocked within the
needle guard housing. The coupling arm is preferably connected to
the needle trap. In one preferred embodiment, the coupling arm is
connected to an end of the needle trap, in particular to a second
end of the needle trap opposite the first end. The connection
between the coupling arm and the needle trap is preferably pivotal
and may be a resilient pivotal connection.
[0068] In one preferred embodiment, the resilient arm, the needle
trap and the coupling arm are formed as a single component, with
resilient pivotal connections between the resilient arm and the
needle trap and between the needle trap and the coupling arm, the
resilient connections biasing the needle trap into the protected
position and the coupling arm out of engagement with the catheter
hub.
[0069] The position of the needle trap is preferably stabilised
both by the coupling arm engaging with the wall of the needle guard
housing on one side of the needle shaft and by the resilient arm
engaging the wall of the needle guard housing on the opposite side
of the needle shaft. In one preferred embodiment, the coupling arm
extends through an opening in the wall of the needle guard
housing.
[0070] In one embodiment, the coupling arm extends around the
needle shaft in the ready position, preferably within the needle
guard housing. In a preferred embodiment, the coupling arm
comprises an opening, the needle shaft extending through the
opening in the coupling arm in the ready position.
[0071] In the protected position, the needle trap extends distally
across the sharpened needle tip and prevents the needle moving in
the distal direction relative to the needle guard assembly. The
needle guard assembly further comprises means for limiting movement
of the needle in the proximal direction relative to the needle
guard assembly, so as to prevent the needle guard assembly from
leaving the distal end of the needle. The limiting means may
comprise a tether, for example extending between the needle hub and
the needle guard housing. Preferably, the needle comprises a bulge,
such as a crimp, in the distal end portion of the needle shaft
spaced from the needle tip. The needle guard assembly, preferably
the needle guard housing, comprises a proximal wall having an
opening therein, the needle shaft extending through the opening in
the proximal wall. The bulge in the needle shaft has a radial
dimension that is larger than that of the opening in the proximal
wall, such that the bulge and the distal end of the needle cannot
pass through the opening. The region of the proximal wall
surrounding the opening may be reinforced, for example by way of a
metal ring or washer, to prevent the bulge in the needle shaft
being inadvertently pulled through the proximal wall of the
housing. This is particularly advantageous when the needle guard
housing is formed from a relatively soft material, such as plastic.
In the ready position, the bulge in the needle shaft preferably
lies within the hollow catheter. When the bulge is non-circular it
has the advantage of allowing blood to flow between the inside of
the catheter and the outside of the needle, to provide the
secondary blood flashback.
[0072] In a further aspect, the present invention provides an IV
catheter assembly comprising a needle guard assembly as
hereinbefore described.
BRIEF DESCRIPTION OF THE DRAWINGS
[0073] Embodiments of the present invention will be described, by
way of example only, having reference to the accompanying drawings,
in which:
[0074] FIG. 1 is a cross-sectional view of a device according to a
first embodiment of the present invention in a ready position;
[0075] FIG. 2 is a cross-sectional view of the device of FIG. 1 in
the direction II;
[0076] FIG. 3 is a cross-sectional view of the device of FIG. 1 in
a retracted position;
[0077] FIG. 4 is a cross-sectional view of a device according to a
second embodiment of the present invention in a ready position;
[0078] FIG. 4a is an enlarged cross-sectional view of the needle
guard assembly of the device of FIG. 4;
[0079] FIG. 5 is a cross-sectional view of the device of FIG. 4 in
a protected position;
[0080] FIG. 5a is an enlarged cross-sectional view of the needle
guard assembly of the device of FIG. 5a;
[0081] FIG. 6 is a cross-sectional view of a device according to a
third embodiment of the present invention in a ready position;
[0082] FIG. 7a is a cross-sectional view of a valve assembly for
use in the devices of any of FIGS. 1 to 6;
[0083] FIG. 7b is a proximal end view of one embodiment of the
valve assembly of FIG. 7a;
[0084] FIG. 7c is a proximal end of a second embodiment of the
valve assembly of FIG. 7a;
[0085] and
[0086] FIG. 8 is a perspective view of one embodiment of needle
guard for use in the catheter assembly of the present
invention.
DETAILED DESCRIPTION
[0087] Referring to FIGS. 1 and 2, there is shown a device
according to a first embodiment of the present invention, generally
indicated as 2. The device 2 is shown in FIGS. 1 and 2 in a ready
position. The device is shown in FIG. 3 in a retracted position,
that is with the needle withdrawn in the proximal direction.
[0088] The device 2 comprises a catheter hub 4 having a distal end
6 and a proximal end 8. An elongate, hollow, tubular catheter 10 is
connected to the catheter hub 4 and extends from the distal end 6
of the catheter hub, in known manner. The catheter hub 4 comprises
an internal chamber 12. The internal chamber 12 is open at the
proximal end 8 of the catheter hub 4 and communicates with the
hollow catheter 10 at the distal end of the catheter hub. Details
of the catheter hub are described in more detail below.
[0089] A generally cylindrical needle hub 20 has a distal end 22
and a proximal end 24. The needle hub 20 is formed with an internal
chamber 26, the open proximal end of which is closed by a vented
flashback plug 28. In use, the chamber 22 in the needle hub 20
serves as a flashback chamber for the user to observe blood
flashback, again in known manner.
[0090] A needle 30 is connected at its proximal end 32 to the
distal end 22 of the needle hub 20. The needle 30 has a shaft 34
with a bore therethrough and having a sharpened needle tip 36 at
its distal end. In the ready position, shown in FIGS. 1 and 2, the
needle 30 extends through the internal chamber 12 of the catheter
hub 4 and through the catheter 10, such that the sharpened needle
tip 36 extends beyond the distal end of the catheter 10.
[0091] The needle 30 can be provided with a slot 38 in the distal
end portion of the needle and spaced from the sharpened needle tip
36. In the ready position, the slot 38 lies within the catheter 10.
In use, blood entering the bore in the needle shaft 34 flows out
through the slot 38 and between the needle shaft 34 and the inner
surface of the catheter 10 and provides a flashback indication to
the user to indicate that the needle tip is properly located within
a vein of the patient. Blood flowing through the bore in the needle
shaft 34 enters the internal chamber 26 of the needle hub 20 and
provides a primary flashback indication to the user, as mentioned
above.
[0092] As noted above, the device 2 comprises a catheter hub 4
having an internal chamber 12. The catheter hub 4 has a proximal
portion 40 and a distal portion 42. The internal chamber 12 is open
at the proximal end 8 of the catheter hub 4 and extends through
both the proximal and distal portions 40, 42 of the catheter hub 4,
to communicate with the hollow catheter 10. The proximal portion 40
of the catheter hub 4 is generally conical in configuration and is
formed with an internal taper 44, in particular a female Luer taper
of standard form. The proximal portion 40 of the catheter hub 4 is
provided with a protrusion 46 extending into the internal chamber
12 and located distally of the Luer taper. In the embodiment shown
in FIGS. 1 and 2, the protrusion 46 is in the form of a
circumferentially extending ring.
[0093] A valve opener 50 is disposed in the proximal portion 40 of
the catheter hub 4. The valve opener 50 has an elongate stem 52 and
a conical head 54 disposed at the distal end of the shaft 52. A
bore extends longitudinally through the valve opener 50 and
receives the shaft of the needle 30 in the ready position, as shown
in FIGS. 1 and 2. The valve opener 50 is retained within the
internal chamber 12 of the catheter hub 4 and its movement in the
proximal direction is limited by the protrusion 46. The valve
opener 50 is free to move in the distal direction under the action
of a male fitting, such as a syringe, inserted into the proximal
end 8 of the catheter hub 4.
[0094] The distal portion 42 of the catheter hub 4 has a generally
flat profile, as shown in FIGS. 2 and 3, with wing members 60
extending from opposing sides of the catheter hub 4. The wing
members 60 provide a means for securing the catheter hub 4 to the
skin of a patient, for example by a suitable medical grade adhesive
tape.
[0095] The proximal and distal portions 40, 42 of the catheter hub
4 may be formed as a single component or may be formed separately
and thereafter joined together in the arrangement shown in FIGS. 1
to 3.
[0096] A flexible extension tube 62 extends from the distal portion
42 of the catheter hub 4. The distal end of the extension tube 62
opens into the internal chamber 12 of the catheter hub. The
proximal end of the extension tube 62 is provided with a hollow
connecting hub 64 having a proximal opening and provided with an
internal taper, in particular a standard female Luer taper, for
accepting a fitting, such as a syringe and the like, in known
manner. A vented plug 66 may be provided at the proximal end of the
connecting hub 64, as shown in FIG. 1, to maintain sterility. The
connecting hub 64 may be used to introduce fluid into the extension
tube 62 and the catheter assembly 2, for example by way of a
syringe 68, shown in FIG. 3.
[0097] The distal portion 42 of the catheter hub 4 is further
provided with a valve assembly 70 therein. The valve assembly 70 is
disposed within the internal chamber 12 of the catheter hub and
comprises a first valve portion 72, disposed in the internal
chamber 12 distal of the valve opener, and a second valve portion
74, distal of the first valve portion.
[0098] The function of the first valve portion 72 is to seal the
internal chamber 12 within the catheter hub 4, to prevent the flow
of fluids in either the proximal or distal direction when the first
valve portion is closed. The first valve portion 72 comprises a
flexible valve disc 76 extending laterally across the internal
chamber 12 of the catheter hub 4. The valve disc 76 is of a
flexible, resilient material. The valve disc 76 is provided with
one or more radial slits therein. In this way, the shaft 34 of the
needle 30 extends through the valve disc 76 in the ready position,
shown in FIGS. 1 and 2. Details of embodiments of the valve
assembly are shown in FIGS. 7a to 7c and described hereinbelow.
[0099] With the needle in the ready position, the valve disc 76
closes around the outer surface of the needle shaft 34. With the
needle 30 in the ready position, the slits are held open a
sufficient distance to allow air to vent through the valve disc in
the proximal direction, while being sufficiently closed so as to
prevent the flow of blood through the valve disc in the proximal
direction. By allowing air to vent through the valve disc 76 in
this manner, the flow of blood from the slot 38 in the needle shaft
34 within the catheter 10 along the outside of the needle is
possible, or without the slot 38 in the needle, as the needle tip
is withdrawn into the hollow catheter tubing, thereby providing the
secondary flashback.
[0100] The first valve portion 72 is a two-way valve. With the
needle 30 retracted and the valve disc 76 closed, the flow of fluid
in either the distal or the proximal direction within the catheter
hub 4 is prevented. When there is no valve opener 50, then the
valve disc 76 opens under the action of a reduced fluid pressure on
the proximal side of the valve disc 76, for example by applying a
vacuum to the proximal end of the catheter hub with a syringe
engaged with the proximal end of the catheter hub 4. In this way,
fluid may be withdrawn in the proximal direction through the
catheter hub from the catheter 10 to the proximal end 8 of the
catheter hub 4. Applying an increased fluid pressure to the
proximal side of the disc valve 76, for example by way of a syringe
engaged with the proximal end of the catheter hub 4, opens the
valve and allows the passage of fluid in the distal direction
through the catheter hub. In this way, fluid may be infused to the
patient through the catheter hub 4 and catheter 10.
[0101] Engaging a fitting to the proximal end 8 of the catheter hub
4, such as a syringe or the like having a male taper, in particular
a standard male Luer taper, urges the valve opener 50 in the distal
direction. Movement of the valve opener 50 in the distal direction
causes the head 54 of the valve opener to contact the valve disc 76
and open the slits in the disc. Fluid may be withdrawn from or
infused to the patient with the valve open in this manner. The
valve disc 76 is formed from a resilient material. As the male
fitting is removed from engagement with the proximal end 8 of the
catheter hub 4, the valve opener 50 is urged in the proximal
direction by the valve disc 76 until the slits in the valve disc
close. As noted above, further movement of the valve opener 50 in
the proximal direction is prevented by the protrusion 46 in the
proximal portion of the catheter hub 4.
[0102] The second valve portion 74 is disposed within the internal
chamber 12 of the catheter hub 4 distal of the first valve portion
72. The function of the second valve portion 74 is to seal the
opening in the distal end of the extension tube 62. The second
valve portion 74 is in the form of a tube 80 of flexible, resilient
material extending around the circumference of the internal chamber
12 of the catheter hub 4. The tube 80 conforms to the inner surface
of the distal portion 42 of the catheter hub and provides a
fluid-tight seal against the inner surface. The internal chamber 12
within the distal portion 42 of the catheter hub 4 may be generally
cylindrical, in which case the tube 80 is generally cylindrical.
Alternatively, the internal chamber 12 within the distal portion 42
of the catheter hub 4 may be elliptical in cross-section. The tube
80 for such an arrangement is also elliptical in cross-section.
Embodiments of the valve assembly are shown in FIGS. 7a to 7c and
described in more detail below.
[0103] As noted above, the tube 80 seals the distal end of the
extension tube 62 at its opening into the internal chamber 12 in
the catheter hub 4. An interference fit between the tube 80 and the
catheter hub 4 urges the outer surface of tube 80 into contact with
the inner surface of the distal portion 42 of the catheter hub,
forming a fluid-tight seal. Increased fluid pressure within the
extension tube 62 urges a portion of the tube 80 away from the
inner surface of the internal chamber 12, allowing fluid to flow
from the extension tube 62 into the internal chamber 12 and in a
distal direction to the catheter 10. In this way, fluid may be
introduced into the catheter 10 by way of the extension tube 62,
for example from a syringe 68 connected to the connecting hub 64,
as shown in FIG. 3.
[0104] In order to ensure a distally directed infusion towards the
hollow catheter tubing, the proximal end of the tube 80 may be
further stiffened by inserting a hard ring at the proximal end of
the tube 80 just distal of the disc 76 or a flange can be extended
from disc 76 that is held in a groove in the inside surface of the
catheter hub.
[0105] Turning to FIGS. 4 and 5, there is shown an alternative
embodiment of the device of the present invention. The device of
this embodiment, generally indicated as 102, comprises a catheter
hub, catheter, needle hub and needle, valve assembly and valve
opener, and extension tube of the same general configuration as the
embodiment of FIGS. 1 and 2 and described above. Features of the
embodiment of FIGS. 3 and 4 common to the embodiment of FIGS. 1 and
2 are indicated using the same reference numerals.
[0106] The embodiment of FIGS. 3 and 4 comprises a needle guard
assembly disposed between the distal end of the needle hub 20 and
the proximal end of the catheter hub 4, when the device is in the
ready position, as shown in FIG. 3. The needle guard assembly,
generally indicated as 120, is shown in the ready position in
greater detail in FIG. 4a.
[0107] There can be some overlapping of the proximal end of the
needle guard and the distal end of the needle hub and/or
overlapping of the distal end of the needle guard and the proximal
end of the catheter hub.
[0108] Referring to FIG. 4a, the needle guard assembly 102
comprises a generally cylindrical needle guard housing 122 having a
proximal end 124 and a distal end 126. Alternative shapes for the
needle guard housing include a generally rectangular cross-section.
The distal end portion is conical in form and provided with a
standard taper, in particular a standard male Luer taper. In the
ready position shown in FIG. 3, the conical distal end 126 of the
needle guard housing 122 extends within the female Luer taper in
the proximal end 8 of the catheter hub 4.
[0109] The needle guard housing 122 comprises an internal chamber
128 open at the distal end 126 and closed at the proximal end 124
by a proximal wall 130. In the ready position, the needle shaft 34
extends through the internal chamber 128 of the needle guard
housing 122 and the proximal wall 130, as shown in FIGS. 4 and
4a.
[0110] A needle guard 140 is disposed within the needle guard
housing 122 and comprises a needle trap 142 having lateral or side
members 144 extending proximally from the needle trap 142. The
needle trap further comprises a retaining member 146. When the
needle 30 is retracted to the protected position shown in FIG. 5,
the side members 144 and retaining member 146 prevent the needle
trap 142 moving laterally relative to the needle and exposing the
needle tip.
[0111] The needle guard 140 further comprises a resilient arm 150
pivotally connected at a first end 152 to the needle trap and
bearing on the inner surface of the needle guard housing 122 at a
second end.
[0112] The needle guard 140 further comprises a coupling arm 160
pivotally connected at a first end to the needle trap 142 at a
position opposite to the connection between the needle trap and the
resilient arm 150. The coupling arm 160 extends from the needle
trap 142 across the internal chamber 128 and through an opening 162
in the needle guard housing 122. The coupling arm 160 is provided
with a hook 164 at its free end outside the needle guard housing
122, which engages with a flange 166 on the exterior of the
proximal end 8 of the catheter hub 4, as shown in FIG. 4. An
opening 168 is provided in the coupling arm 150, through which the
needle shaft 34 extends in the ready position, as shown in FIG.
4a.
[0113] In the ready position shown in FIGS. 4 and 4a, the needle
trap 142 is held to one side of the needle shaft 34 in a folded
position overlying the resilient arm 150. The coupling arm 160 is
held by the needle shaft 34 retracted within the needle guard
housing 122, in turn holding the hook 164 engaged with the flange
166 on the proximal end 8 of the catheter hub 4.
[0114] The needle guard 140 is inherently resilient urging the
needle guard into a straight orientation. In the ready position the
needle shaft 34 holds the needle trap 142 against the inherent bias
of the needle guard. When the needle 30 is retracted to the
protected position shown in FIGS. 5 and 5a, in particular, when the
needle tip 36 is moved to a position within the needle guard
housing 122 proximal of the needle trap and the coupling arm, the
resilience of the needle guard 140 urges the needle trap 142 into
the blocking position across the needle tip 36. The same movement
urges the hook 164 of the coupling arm out of engagement with the
proximal end 8 of the catheter hub 4, thereby releasing the needle
guard assembly 120 from the catheter hub. The retaining member 146
is positioned to engage with the needle shaft at the sharpened
needle tip 36 to prevent the coupling arm being pushed in the
reverse direction in the needle guard housing and realigning the
opening 168 in the coupling arm with the needle tip 36.
[0115] As shown in the figures, the needle shaft 34 extends through
an opening 170 in the proximal wall 130 of the needle guard housing
122. The needle 30 is provided with a bulge, in the form of a crimp
172, in the distal end portion of the needle shaft spaced from the
needle tip 36. In the ready position, the crimp 172 is located
within the catheter 10. The crimp 172 has a diameter greater than
the radial dimension of the opening 170 in the proximal wall 130 of
the needle guard housing 122. In the protected position shown in
FIGS. 5 and 5a, the needle tip 36 is within the needle guard
housing 122. The needle 30 is prevented from moving distally
relative to the needle guard assembly 120 by the needle trap 142.
Further proximal movement of the needle 30 relative to the needle
guard assembly 120 is prevented by the crimp 172 engaging with the
proximal wall 130, as shown in FIG. 5a. A metal washer 174 may be
provided on the inner surface of the proximal wall 130, to engage
with the crimp and prevent the crimp 172 being inadvertently pulled
through the proximal wall. This allows the needle guard housing 122
to be formed from a relatively soft material, such as moulded from
plastic.
[0116] Turning to FIG. 6, there is shown an alternative embodiment
of the device of the present invention. The device of this
embodiment, generally indicated as 202, comprises a catheter hub,
catheter, needle hub and needle, valve assembly and valve opener,
and extension tube of the same general configuration as the
embodiment of FIGS. 1 and 2 and described above. Features of the
embodiment of FIG. 6 common to the embodiment of FIGS. 1 and 2 are
indicated using the same reference numerals. The embodiment of FIG.
6 also comprises a needle guard assembly having a needle guard of
the same general configuration as that of the embodiment of FIGS. 4
and 5. Features of the embodiment of FIG. 6 common to the
embodiment of FIGS. 4 and 5 are indicated using the same reference
numerals.
[0117] The device is shown in the ready position in FIG. 6. In the
needle guard assembly 120 of FIG. 6, the needle guard housing 122
is located wholly outside the catheter hub 4. The needle guard
assembly 120 is coupled to one side of the flange 166 of the
proximal end of the catheter hub 4 as in FIG. 4 and described
above. To stabilise the needle guard housing 122 on the proximal
end of the catheter hub 4, the needle guard housing is provided
with an exterior distal arm 210 extending from the distal end 126
of the housing on the opposite side to the coupling arm 160. The
exterior distal arm 210 engages with the exterior flange 166 at the
proximal end of the catheter hub on the opposite side of the
catheter hub to the engagement of the coupling arm 160.
[0118] As the needle is retracted to the protected position, the
coupling arm 160 and its hook 164 are released from the flange 166
of the catheter hub 4. The exterior distal arm 210 is thereby
released from engagement with the flange 166 and the needle guard
assembly 120, with the blocked needle tip 36 therein, may be
removed from the catheter hub 4.
[0119] Turning to FIG. 7, embodiments of the valve assembly for use
in the distal portion 42 of the catheter hub 4 will now be
described.
[0120] Referring to FIG. 7a, there is shown a longitudinal
cross-sectional view of a valve assembly for use in the catheter
assembly of the present invention. The valve assembly, generally
indicated as 702, is formed from a flexible material impermeable to
the passage of liquid and gas. The valve assembly 702 comprises a
generally tubular first valve portion 704 and a second valve
portion in the form of a valve disc 706 at the proximal end of the
first valve portion.
[0121] Views of the valve disc 706 of embodiments of the valve
assembly 702 are shown in FIGS. 7b and 7c. The valve assembly 702
may have a generally circular cross-section, as shown in FIG. 7b.
Alternatively, the valve assembly 702 may be generally flattened
and have an elliptical cross-section, as shown in FIG. 7c. The
portion of the internal chamber 12 within the distal portion 42 of
the catheter hub 4 will conform in shape to the valve assembly 702,
such that the valve assembly is a tight fit within the chamber and
the first valve portion 704 is in close contact with the inner
surface of the chamber, so as to provide a fluid tight seal between
the valve assembly and the inner surface of the catheter hub.
[0122] The valve disc 706 is provided with a plurality of slits 708
therein. The embodiments shown in FIGS. 7b and 7c each have an
array of three slits extending radially outwards from the centre of
the valve disc 706. Other arrangements of the slits 708 in the
valve disc 706 are possible, for example a single slit.
[0123] In the ready position, the shaft 34 of the needle extends
through the valve disc 706. The shaft of the needle holds the slits
708 open sufficient to allow gas to pass through the valve disc, in
particular in the proximal direction, but insufficient to allow
blood to pass through the valve disc. In this way, the user may be
provided with a flashback indication, as described above.
[0124] As described above, the valve disc 706 is resilient. In
particular, the valve opener 50 moves in the distal direction
against the resilient bias of the valve disc, when acted upon by a
male fitting inserted into the proximal end 8 of the catheter hub
4. Upon removal of the fitting, the valve disc urges the valve
opener in the proximal direction, allowing the valve disc to close
and seal the internal chamber of the catheter hub.
[0125] As noted above, the needle guard may be of an arrangement
that is retained within the catheter hub in the ready position. One
preferred embodiment of such a needle guard is shown in FIG. 8. The
needle guard is in the form of a needle clip, generally indicated
as 802, which is made of a resilient material, such as metal,
having arms 804, 806 extending in a distal direction from opposite
sides of a proximal wall 810. The proximal wall 810 has a hole 812
for the passage of the needle. The needle shaft is provided with a
bulge, for example in the form of a crimp, proximal of the tip of
the needle as described hereinbefore and shown in the figures. The
diameter of the hole 812 in the proximal wall 810 of the needle
clip 802 is smaller than the maximum transverse dimension of the
needle at the bulge, so that the needle clip 802 is held in the
protected position on the needle tip by means of the bulge.
[0126] In the embodiment shown in FIG. 8, the arms 804, 806
intersect and extend on both sides of the needle and each has at
its distal end an end portion 820, 822 which is widened to
approximately the width of the proximal wall 810 and which, in the
ready position, lies with elastic pretensioning on the outer
circumference of the needle. Alternatively the arms do not have to
cross and can extend along opposing sides of the needle shaft. Upon
reaching the needle tip, the distal end portions 820, 822 are moved
by spring action into the protected position in which the two
widened end portions 820, 822 engage over and block the needle tip.
For this purpose, the distal ends 820, 822 of the arms 804, 806 are
slightly offset with respect to one another in the longitudinal
direction or the arms 804, 806 are of different lengths, so that it
is thus ensured that the two distal end portions 820, 822 of the
arms engage over the needle tip. Alternatively only the longer arm
806 can have an end portion 822 to block the needle tip.
Preferably, the longer arm 806 has an endmost portion 824 curved
inward at the free edge, in order to ensure that the needle tip is
covered even if an attempt is made to push the needle clip 802 back
from the protected position on the needle, the inwardly curved end
portion 824 hooking onto the needle tip. The needle clip 802 as a
whole can be made very compact and only about 7 mm long, for
example.
* * * * *